Search and rescue operations continued on Monday for four missing crew members, five days after a barge capsized in Singapore waters.

On Sunday, a sailor from the capsized Bolivia-flagged Heng Hong 168 was found drifting in waters off Bintan island. The Maritime and Port Authority of Singapore (MPA) said in a statement that the rescued crew member has been admitted to a hospital in Bintan for observation.

The barge had capsized on Thursday in Singapore waters, and the Police Coast Guard rescued six crew members on the same day. MPA had reported then that the six men were well and did not require medical attention.

Both Singapore and Malaysian authorities are involved in the search and rescue operation, which includes air and sea searches, as well as commercial divers.